Transferrin-grafted catanionic solid lipid nanoparticles for targeting delivery of saquinavir to the brain

•Particle size of Tf/SQV-CASLNs increases with an increasing level of catanionic surfactants.•Viability of HBMECs enhances with an increasing weight percentage of Compritol 888 ATO.•Viability of HBMECs reduces with an increasing level of catanionic surfactants.•The order of Compritol 888 ATO in the permeability of SQV across the BBB is 33% > 100% > 0%.•Transferrin on SQV-CASLNs enhances the permeability of SQV across the BBB.

Saquinavir (SQV)-loaded catanionic solid lipid nanoparticles (CASLNs) were grafted with surface transferrin (Tf) (Tf/SQV-CASLNs) for targeting the blood–brain barrier (BBB). Tf/SQV-CASLNs were cultured with human brain-microvascular endothelial cells (HBMECs) to demonstrate the particulate uptake via Tf receptors for the BBB transport. The results revealed that an increase in the concentration of catanionic surfactants from 1 mM to 2 mM enlarged the average diameter of Tf/SQV-CASLNs from 150 nm to 500 nm. An increasing weight percentage of Compritol 888 ATO (CA) in lipids enhanced the viability of HBMECs. However, an increasing concentration of catanionic surfactants reduced the viability. The order of the CA weight percentage in the permeability of SQV using Tf/SQV-CASLNs to cross the BBB is 33% > 100% > 0%. In addition, an increase in the concentration of Tf on Tf/SQV-CASLNs enhanced the BBB permeability of SQV. Tf/SQV-CASLNs fabricated with 33% (w/w) CA in the lipid phase, catanionic surfactants of 1 mM, and Tf of 30 μg/mL can be efficient colloidal carriers for delivering SQV into the brain.